1. Field
The disclosed embodiments concern a device for non-destructive testing of a structure by vibratory analysis, containing means to measure the vibratory waves emitted by the structure so as to identify abnormal vibrations caused by a defect in the structure. The means of measuring are incorporated into a flexible housing capable of adhering to the surface of the structure to be tested. The disclosed embodiments have applications in the non-destructive testing (NDT) of aircraft structures, but may be used in any industrial sector where testing the integrity of workpieces is important, such as the automotive, railroad, naval-construction, or nuclear sectors.
2. Brief Description of Related Developments
In the operation and maintenance of aircraft, it is necessary to employ testing methods that can determine whether the structures have been damaged by cracks or fissures, without harming the parts constituting the structure. The techniques used are jointly referred to as “non-destructive testing” (NDT). NDT techniques are numerous and constantly changing, because the industrial sectors concerned have a need for improved performance from these NDT techniques. The air-transport and civil-engineering sectors are always on the lookout for ever more effective NDT techniques to meet the dual requirements of safety and their desire for cost-reduction.
Accordingly, the disclosed embodiments are designed specifically to detect abnormal vibrations in aircraft structures while the aircraft is in flight. In some cases these vibrations are indicators of the appearance of defects in the structures, e.g., the development of fissures or cracks in the material constituting the aircraft's structure.
For example, there are means of testing by using x-ray radiography or magnetic induction that can detect defects in a structure, but these means are difficult to apply, and unsuitable for use on an aircraft structure unless the aircraft is stationary.
There are also visual testing means for detecting the appearance of fissures, but in general the structures in which defects are most likely to develop are structures that present access difficulties, such as fastenings or complex moving structures. These means enable the detection of fissures only when the fissures emerge on a surface directly accessible to the operator, thus visual testing means do not provide for effective predictive maintenance of the structures.
All of these means of testing require that the aircraft be immobilized on the ground for the conduct of an inspection of the sensitive areas of the aircraft using the testing apparatus. This entails a relatively long testing period and the presence of a qualified operator, thereby leading to a relatively high maintenance cost.
As far as the designer of this device knows, there is currently no effective means for inspecting the status of structures, e.g., aeronautical structures, throughout their periods of use, and in particular for carrying out an overall evaluation of the health of aeronautical structures while the airplane is in flight.